shared_ptr -> std::shared_ptr

This is one of the first commits in a plan to remove all `using namespace std;` lines in the entire codebase as it is considered anti-pattern today.

Minecraft.World/SetCreativeModeSlotPacket.cpp

@@ -11,11 +11,11 @@ SetCreativeModeSlotPacket::SetCreativeModeSlotPacket()
 	this->item = nullptr;
 }
 
-SetCreativeModeSlotPacket::SetCreativeModeSlotPacket(int slotNum, shared_ptr<ItemInstance> item)
+SetCreativeModeSlotPacket::SetCreativeModeSlotPacket(int slotNum, std::shared_ptr<ItemInstance> item)
 {
 	this->slotNum = slotNum;
 	// 4J - take copy of item as we want our packets to have full ownership of any referenced data
-	this->item = item ? item->copy() : shared_ptr<ItemInstance>();
+	this->item = item ? item->copy() : std::shared_ptr<ItemInstance>();
 }
 
 void SetCreativeModeSlotPacket::handle(PacketListener *listener)